Method and apparatus for rolling tubular articles



May 27, 1930. H. s. NEWLIN ET AL I 1,760,278

METHOD AND APPARATUS FOR ROLLING TUBULAR ARTICLE Filed Oct. s, 1927 gap-Z l rm gag z Z v employing inner and outer rolls.

Patented May 27, 1930 UNITED STATES PATENT OFFICE HENRY S. NEWLIN, 0F JERSEY CITY, AND WILLIAM DATE, OF EAST ORANGE, NEW

JERSEY; SAID NEWLIN ASSIGNOR TO THE M. YORK, N. Y., A CORPORATION OF DELAWARE w. KELLOGG COMPANY, OF NEW METHOD AND APPARATUS FOR ROLLING TUBULAR ARTICLES Application flledOctober 8, 1927. Serial No. 824,892.

. This invention relates to a load e ualizer and more particularly to a method an means for equalizing the load in arolling machine In the 0 eration of rolling, it is often desirable, as or example in the rolling of large cylindrical bodies of tubular form, to employ both inner'and outer rolls. In rolling small cylinders the work is ordinarily all done by the outer roll and its motor, the inner roll and motor idling with no current on the motor. When rolling larger cylinders where it is desirable to use both rolls the diiiiculty is encountered that as the thickness of the cylinder is constantly decreased the inside peripheral speed of the cylinder is constantly increased. In order to meet this condition and to keep both rolls doing effective work, the speed of the inside roll must be increased so as to keep the peripheral speed thereof synchronized with the inside peripheral speed of the cylinder. Unless this is done there will be a tendency for the rolls to exert a tearing action upon the metal and to set up stresses in the walls of the article produced. At the same time the load will be unequally distributed between the motors operating the respective rolls.

It is accordingly the aim of this invention to provide a method and means by which the load may be equalized between two motors, the speed of one of which is constantly increasing.

A further object of the invention is to provide a means for constantly increasing the drical billets or ingots.

Fig. 2 is a vertical section on the line 22 of Fig. 1 illustrating the relation of the rolls to the cylindrical body being rolled and a.

Fig. 3 is a diagrammatic showing of the layout of the electric circuits used in controlling the operation of the roll-actuating motors.

As shown in the drawing a hollow billet or ingot 10 is placed upon the upper roll 11 and the lower roll 12 is brought into contact with the outside of the billet 10. The

a motor M It will be apparent that when pressure is applied to the rolls the hollow billet 10 will expand on its diameter and, that as its walls become thinner its inside peripheral speed will tend to approach that of the outside. Therefore, if the roll 12 is rotated at a constant speed, the speed of the upper roll 11 will have to be constantly increased. To accomplish this and to e ualize the load between the motors M and 2 we provide an automatic control mechanism as is indicated diagrammatically in Fig. 3. In this figure, M and M indicate the armatures of the motors M and M respectively. F and F represent the fields of these motors.

At 13 and 14 are shown lungers which act respectively as the solenold cores for the coilsg a id V on the one hand and the coils C and V on the other. The coils V and V are connected across lines L and L leading to a suitable source of current supply as'indicated at 15 and 16 and the flow of current through such coils is controlled by means of the rheostats R and R It will, therefore,

be seen that the coils V and V function as voltage coils and compensate for any variation in the line voltage. Since with constant power output any drop in voltage will be accompanied by an increase in amperage, it will be seen that thev magnetic pull on the solenoid cores 13 and 14 will be balanced so long as the power or wattage applied to each motor is the same, because any weakening of one of the voltage coils V or V due to a drop in voltage will simply mean the strengthening of the corresponding current of the electrical energy passing throughv them.

The solenoid cores or plungers 13 and 14 are connected to the respective arms of the rock-lever device 17 fulcrumed at 18 and hav ing switch arms 19 and 20. The arm 19 is arranged to close a circuit by means of the contacts 21 and 22 through one field of the split field motor M and'the arm 20 is arranged to close a circuit by means of'the contacts 23 and 24 through the other field of the split field motor M The motor M is connected to "operate a field rheostat R which is adaptedto strengthen or weaken the field F of the variable speed motor M The motor M having shunt field speed.

As illustrative of the operation of the apparatus, let us assume that a hollow cylindrical blank or billet has been placed in the rolls. The current is turned on and the motors caused to come to approximately the same speed as determined by the constant speed setting of the motor M If during the course of the rolling operation the motor M is lagging behind the motor M in speed, then it is evident that more'current will be flowing through the motor M. This will cause the magnetic pull of the coils V and C on the solenoid core 13 to exceed that exerted by the coils V and C on the solenoid core 14, thereby causing the rock lever device 17 to turn on its fulcrum at 18 and close the contacts 23 and 24 and through them the circuit through one field of the motor M The motor M will then operate to change the setting of the rheostat R and cause the speed of the motor M to increase until the proper speed setting is reached. Should the motor M tend to assume more than its share of the load, then the reverse will take place.

If it is desired that one of the motors M and M should assume more of the load than the other, this may be accomplished by suitably adjusting the rheostats R and R While the invention has been described with particular reference to the use of direct current motors it will be understood that with very slight modifications of the wiring and circuit connections it may be applied to I claims. 1

alternating current induction motors of the wound rotor type.

It will be further understood that instead of continuously increasing the speed of one of the motors while maintaining the other constant the circuit arrangement may be such that the speed of one of the rolls is maintained constantwhile the other is progressively decreased. f

It is also to be understood that various other modifications and changes may be made without departing from the scope of the invention, which is not to be deemed to be limited other than as indicated by the appended What we claim is 1. The method of equalizing the load be tween two motors the speed of one of which varies continuously, which comprises tying the said motors together through a difi'erential load control device consisting of a pivoted bar member having contact means at either end, magnets connected with either end of said bar and energized by the respective motor circuits, said magnets when unequally energized being adapted to turnsaid pivoted member to make contact with a rheostat member connected to each motor circuit and causing the speed of one motor to increase.

until both magnets are energized equally.

2. In a rolling mill, rolls for engaging a tubular blank and applying rolling pressure to the inner and outer surfaces of saidblank,

'. motors for operating said rolls, and means for controlling the relative speeds of said rolls comprising magnets connected respectively to the respective motor circuits and responsive to difierences in power input to the respective motor circuits, said magnets being connected to a current-controlling mechanism adapted to vary the current supply to one of said motors.

3. In a rolling mill, rolls for engaging a tubular blank and applying rolling pressure to the inner and outer surfaces of said blank, motors for operating said rolls, means for maintaining the speed of'one of said rolls constant, and-means for continuously varying the speed of the other to maintain the peripheral speeds of the two rolls synchronized with the peripheral speeds of the respective surfaces of the blank with which they are in contact, said means comprising solenoids responsive to difference in power input to the respective motors and actuating a motorcontrolled rheostat varying the current input into the motor actuating the variable speed roll.

In testimony whereof, we have signed our names to this specification this fourth day of October, 1927.

' HENRY S. NEWLIN.

WILLIAM E. DATE; 

